PROJECT SUMMARY/ABSTRACT Alcohol use disorders frequently have a pediatric origin. Pediatric primary care offices, where the majority of adolescents receive health care, are a promising venue for early identification and intervention through universal screening and brief counseling. However, while the U.S. Preventive Services Task Force recommends primary care-based alcohol screening and brief intervention for adults, it found insufficient evidence to recommend it for adolescents. The goal of the proposed study is to address this evidence gap by testing the effectiveness of a promising computer-facilitated Screening and Brief Intervention (cSBI) system for delivery by pediatric primary care clinicians to adolescents at well-visits. This cluster-randomized controlled trial will be conducted in the American Academy of Pediatrics' (AAP) Pediatric Research in Office Settings (PROS) national primary care practice-based research network. PROS has demonstrated success in >30 years of practice-based research, with >600 practices participating in recent studies. Drawing on more than 15 years of our prior research on adolescent alcohol screening and brief counseling in primary care offices, the cSBI system was developed to provide a time-efficient and feasible way for pediatric practices to improve both the frequency and quality of alcohol screening and counseling. cSBI includes: 1) computer self-administered screening that adolescents complete prior to seeing their clinician, 2) computer-delivered personalized feedback to the adolescent, 3) 10 interactive psychoeducational pages for the adolescent on substance use health risks, 4) a Clinician Report Form with screen results and prompts that clinicians use to provide motivational interviewing-based individualized counseling, and 5) clinician training materials and protocol. In our New England-based pilot study, we found that, compared to usual care (UC), the cSBI approach: 1) increased patient receipt of alcohol-related counseling during well-visits; 2) improved patients' ratings of the quality of their clinician encounter; and 3) among those who reported past-year use at baseline (n=192), was associated with a 34% lower risk of a heavy episodic drinking episode during 12 months follow-up. cSBI also reduced risk of riding with an impaired driver, a major safety risk associated with alcohol, by 42% among those with prior riding risk. A larger RCT of this approach, which employs an adequately-powered sample and tests generalizability of effects beyond New England, is needed. We propose to randomize >30 pediatric primary care clinicians in 10 practices nationwide to deliver UC or cSBI (1:1) to their eligible and assenting 14- to 17- year-old patients arriving for well-visits. Our aims are to test cSBI's effect on heavy episodic drinking, and on riding with an impaired driver/driving while impaired, during 12 months follow-up among 1,268 adolescents screen-identified as at-risk. If effective, cSBI dissemination could leverage existing AAP platforms including education, teaching, and advocacy, to its 67,000 pediatrician members, greatly increasing the potential for population-level impact of alcohol screening and brief intervention for U.S. adolescents.